Microclimates are wonderful things. What? Why should something small be wonderful? Well, it doesn't really have to be all that small-microclimates are places where the climate differs considerably from the overall conditions of the region. For example, a seep or spring may provide coolness, damp soil, and high humidity in an otherwise dry, hot desert. OK, but why wonderful? Because the more microclimates in a region, the more habitats and the greater the biological diversity.
Long-lasting conditions may even allow relictual
populations of organisms to survive long after other populations
have died out due to changing climates. An outstanding example
occurs in northwestern Chihuahua, near Galeana. The area is of
mesquite grassland, but runoff from a hot spring produces a
microclimate supporting a marsh. Investigators noted that,
"This marsh extends as a small strip, not more than 150
meters in width at any point, along the stream for a distance of
about 3 kilometers". This tiny area supports Meadow Voles
some 250 miles south of the nearest populations to the
north—thanks to the microclimate!
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.
Bradley, W. G., and E. L. Cockrum. 1968. A new
subspecies of the Meadow Vole (Microtus pennsylvanicus)
from northwestern Chihuahua, Mexico. American Museum Novitates
2325:1-7.